Combined liner and matrix system

ABSTRACT

The invention relates to a system and a method for well completion, control and monitoring of processes in a reservoir. A combined prefabricated liner and matrix system ( 4 ) with defined properties for fast and simple well and/or reservoir completion, monitoring and control is provided. An embodiment of the combined prefabricated liner and matrix system  4  comprises an outer perforated tubular pipe/pipe system  6 , an inner tubular screen  7 , and a matrix  8 . A method for control and monitoring of processes in a well or reservoir using the combined liner and matrix system is also described The combined liner/matrix system may be used in any process equipment, like e.g. reactors, separators and storage tanks. The system may also be used in a gas/oil/water producing or injection well for well completion, control and monitoring.

FIELD OF THE INVENTION

[0001] The invention relates to a system and a method for wellcompletion, control, and monitoring of processes in a reservoir. Uses ofthe system and method are also disclosed.

BACKGROUND OF THE INVENTION

[0002] In many wells the hydrocarbon-bearing formation has to bestabilized from collapse of the well bore or cracks around the wellbore. Another reason to stabilize a well bore is to reduce theproduction of fines like sand. In order to attain this, the bore isoften lined with a perforated steel pipe whereafter the space betweenthe bore and the pipe may be packed with gravel or proppant particles asdescribed in WO9954592. In addition different kind of sand filters(gravel or matrixes) may be placed inside (U.S. Pat. No. 5,893,416, U.S.Pat. No. 5,232,048 and U.S. Pat. No. 5,551,513) the steel pipe workingas a liner.

[0003] Usually, during hydrocarbon production a minimum of waterproduction compared to oil or gas is desirable. This is normallyachieved by using techniques to suppress water flooding into thereservoir by altering the production zones or by blocking waterbreakthrough. For sub sea wells separation techniques have beenattempted to accomplish separation of produced water down hole in thewell bore combined with reinjection of the produced water. For example,electric powered centrifugal separators have been positioned downhole togenerate a fluid separation vortex within the downhole separator.Another solution is to install systems of valves and bypass pipelines inthe well bore in order to bypass water production zones (WO9963234).However, such equipment requires power and moving components subject towear and failure. In U.S. Pat. No. 6,015,011 a downhole separation byadjusting the pressure differential across a filter below a packer isdescribed. Other methods proposed to reduce water production in a wellis by water sensitive gels (U.S. Pat. No. 5,609,209), water sensitiveparticles (WO9954592), or by microorganisms in porous particles(WO9936667) placed in gravel packing or reservoir fractures In U.S. Pat.No. 6,015,011 a downhole separation by adjusting the pressuredifferential across a filter below a packer is described.

[0004] In order to optimize the total production of oil and gas from awell, some production zones in a well bore may have to be bypassed orsealed off for a given time. This can be achieved by completing thezones with a cemented liner, which is penetrated mechanically at a latertime by intervention. Another solution is to install systems of valvesand bypass pipelines in the wellbore in order to bypass given productionzones (WO9963234). However, such equipment requires power and movingcomponents subject to wear and failure.

[0005] It is also desirable to be able to monitor the production anddifferent phenomena such as e.g. local variations in pH, salinity,hydrocarbon composition, temperature, pressure, microorganisms, and thedifference between production of formation and/or injection water. Aknown method for monitoring of local flow properties in a well is tolower a logging tool into the well as described in U.S. Pat. No.4,861,986, U.S. Pat. No. 5,723,781 and U.S. Pat. No. 5,8811,807. Thesetools require power and moving components subject to wear and failure.Another method for monitoring the flow is by chemical tracers injected(U.S. Pat. No. 4,420,565 and U.S. Pat. No. 4,264,329) or placed in solidparticle packs placed along the well bore (U.S. Pat. No. 3,991,827 andU.S. Pat. No. 4,008,763). Injection of radioactive isotopes is describedin U.S. Pat. No. 5,892,147. NO-C-309884 belonging to the applicant ofthe present invention describe methods for chemically immobilizing orintegrating tracers in the formation, constructions, or filters aroundthe well. The tracers or tracer carriers are chemically intelligentreleased as a function of specified events as oil or water flow rates.

[0006] The object of the present invention is to provide a new solutionfor low cost, fast and simple well or reservoir completion enabling longtime monitoring and enhanced production from hydrocarbon wells withoutany needs for power or moving components.

SUMMARY OF THE INVENTION

[0007] In accordance with a first aspect the invention provides acombined prefabricated liner and matrix system comprising an outerperforated pipe/pipe system having sufficient strength to work as aliner and/or a sand screener, an inner screen, and a matrix arrangedbetween the outer pipe and inner screen, the combined liner and matrixsystem constituting a prefabricated liner with predefined properties forfast and simple well and/or reservoir completion, monitoring andcontrol.

[0008] The matrix may be porous with a controllable porosity, pore sizeand pore size distribution, and the porosity and hence the permeabilitymay be automatically affected by the environment, e.g. by water or oilflow, or by manual trigging with specific reagents. These may be addedby the use of well known techniques or via injection wells. The matrixis either a bulk form (uniform) having the same shape as the geometricalvolume filled by a monomer/polymer solution prior to polymerization, apackage of at least one type of polymer particle, or a combination ofpolymer particles in a bulk polymer (matrix). The matrix may alsocomprise an inert or porogen medium or compound. It is also possible tostart with an initially compact matrix that becomes porous and permeableas a result of external influence. Both an initially porous and compactmatrix may comprise a polymer or chemical compound reacting at theambient conditions (e.g. temperature, pH, water or triggers) therebyreleasing substances chemically bonded or bonded by adsorption to thematrix into the fluid flow.

[0009] The matrix may further comprise components that are detectableafter release from the matrix, e.g. a chemically intelligent tracer(s)for monitoring, production and/or specific events in the well orreservoir. The tracers may be adsorbed in or chemically bonded to thematrix.

[0010] Preferred embodiments of the liner and matrix element system arestated in the dependent claims 2-22.

[0011] In accordance with a second aspect the invention provides amethod for control and monitoring of processes in a well or reservoirusing the combined liner and matrix element system as given above, themethod comprising:

[0012] providing the combined liner and matrix element system containinga matrix with certain properties based on reservoir data prior toinstallation in the reservoir,

[0013] installing the combined liner and matrix element system in thereservoir, and

[0014] controlling or monitoring the well by interaction with/by meansof the matrix.

[0015] In accordance with a third aspect of the invention the abovecombined liner and matrix system may be used as a combined pipeline inany process equipment, like e.g. reactors, separators and storage tanks.

[0016] The invented liner and matrix element system provides a fast andsimple method for well completion, control and monitoring of processespreferably to be used in any oil, gas or water production or injectionwell. In a well completion parts of the series of elements may be ofunperforated pipe elements.

[0017] The matrix may further comprise components inhibiting orpreventing any unwanted phenomena as e.g. bacteria growth or scaleformation in the matrix.

[0018] The invention may be used in any kind of well bore onshore oroffshore. It may also be used for similar purposes in any processequipment.

BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and further advantages may be more fully understood byreferring to the following description and accompanying drawings ofwhich:

[0020]FIG. 1 is a schematic drawing of a well bore 2 through differentformation layers 1 in a reservoir.

[0021]FIG. 2 shows a schematic drawing of an arbitrary section of a wellbore 2 in a reservoir I before insertion of any liner and matrix elementsystem. The well bore boundary and the fractures 3 in the reservoirformation I are also indicated on the figure.

[0022]FIG. 3 shows a schematic drawing of an arbitrary section of a wellbore 2 in a reservoir 1 after insertion of a combined liner and matrixelement system 4 according to an embodiment of the invention.

[0023]FIG. 4 shows a schematic drawing of an arbitrary section of a wellbore 2 in a reservoir 1 after insertion of a combined liner and matrixelement system 4 where the well is divided into sections according to anembodiment of the invention.

[0024]FIG. 5 shows a schematic drawing of a possible structure designfor the cross to section of a combined liner and matrix element system 4according to an embodiment of the invention, where a flexible perforatedmaterial 9 between outer tube 6 and inner screen 7 forms a part of thecombined liner and matrix element 4.

[0025]FIG. 6 shows a schematic cross wall drawing of a possible designfor a combined liner and matrix element system 4 according to anembodiment of the invention.

[0026]FIG. 7 shows another schematic cross wall drawing of a possibledesign for a combined liner and matrix element system 4 according to anembodiment of the invention.

[0027]FIG. 8 shows a schematic cross wall drawing of a possible designfor a water control function using a combined liner and matrix elementsystem 4 according to an embodiment of the invention, by swelling ofmatrix 8.

[0028]FIG. 9 shows a schematic cross wall drawing of a possible designfor a fluid flow control function using a combined liner and matrixelement system 4 according to an embodiment of the invention.

[0029]FIG. 10 shows a schematic drawing of another combined liner andmatrix element system 4 according to an embodiment of the inventionwhere the outer perforated pipe system 6 consists of an outer sandscreen 19, a spacer 20, a perforated pipe 21, a spacer 22, and aperforated pipe 23.

DESCRIPTION OF THE INVENTION

[0030] The following description of different embodiments of theinvention are intended by way of example only and must not be used aslimiting for the invention.

[0031] The combined prefabricated liner and matrix element system 4preferably to be used in an oil, gas or water producing or injectionwell 2, is shown in FIG. 1. The wellbore boundary 3 is indicated on thefigure. The prefabricated combined liner and matrix element system 4 isinserted into the well bore 2, and may be fabricated in various lengths,strength and with different properties. The well can be divided insections or regions using a plugging system 5. The locations of theplugging system elements may be predetermined, e.g. based on reservoirdata. It can also be based on other type data or experiences. In oneembodiment (FIG. 3) the combined liner and matrix element system 4comprises several elements, each element consisting of an outerperforated pipe/pipe system 6 of sufficient strength to work as a linerand/or sand screen, and an inner tubular screen 7 between which is amatrix 8. The matrix 8 is based on one or several types of polymer orpolymer particles that may have one or several given sizes giving adesired characteristic/property to the matrix. The matrix 8 has anywanted strength and permeability. The polymer particles in matrix 8 mayin addition be carriers for any desired chemical or microorganism forcontrol and/or monitoring purposes. The permeability of the matrix 8 ispredetermined and may vary from zero to 70%. It may be fixed or vary intime according to oil or water flow rates, predetermined timedegradation or sealing, or by chemical trigging. Predetermined holes orslices 10 through matrix 8 and inner screen 7 gives at full open areasnearly free flow of fluids from perforated pipe/pipe system 6. (See e.g.FIG. 6) In order to improve (enhance) free unrestricted flow of fluidsfrom perforated pipe/pipe system 6, an inner screen 16 may be placedbetween pipe/pipe system 6 and matrix 8. Areas of holes or slices 10 ispredetermined and may be fixed or vary in time according to oil or waterflow rates. The holes or slices 10 may be filled with an inert mediumprior to installation in well 2, which degrade in predetermined time atreservoir conditions or by chemical trigging. Decrease of open areatrough hole or slices 10 may be obtained by swelling of the matrix 8.

[0032] The tubular liner and matrix element system 4 as shown in FIG. 1may be prefabricated at any suitable length connected to-each other orto any other pipeline elements in order to form a pipeline easilyinstalled in horizontal, vertical or helical wells. The properties ofthe matrix 8 and shapes, sizes and numbers of holes or slices 10 throughmatrix 8 may be predetermined from reservoir data and may vary at anylength. Each element 4 may be tested before installation in thereservoir. Any element may contain equipment for mechanical or chemicalsealing 5 of the well bore.

[0033] The combined liner and matrix elements system 4 may be producedof any suitable materials given sufficient strength and wantedproperties. The inner diameter or the free space inside an element mustbe sufficient for free flow of any fluids and for handling of any wantedwell tools like measuring equipment or valves.

[0034] The outer perforated pipe/pipe system 6 may be of a constructionhaving sufficient strength to work as a liner and/or sand screener aloneor as an integrated part of the combined liner and matrix element system4, and may be of any metal, polymer or composite material. The outertubular pipe/pipe system 6 may be formed as a single perforated pipe oras a flexible material net or any combinations hereof and may e.g. beany commercial liner or sand screen elements.

[0035] The inner screen 7 may be of sufficient mechanical strength tohandle any flow or well tool inside the elements (central well hole 2)and be an integrated part of the liner and matrix element system 4. Theinner screen 7 may be of any metal, polymer or composite material. Itmay be formed as a single perforated pipe or as a flexible material net.The outer perforated tubular pipe/pipe system 6, the inner screen 7, andthe matrix 8 are shown in FIG. 3.

DETAILED DESCRIPTION

[0036] In FIG. 4, the well bore 2 and the combined liner and matrixelement system 4 are divided into three separate sections or zones byplugging system 5. The combined liner and matrix element system 4 usedin various sections of the well may have different properties, lengthsand strength. The injection or squeezing of the plugging system 5 may bemade after the insertion of the combined liner and matrix element system4 into the wellbore 2.

[0037] In the invented combined liner and matrix element system 4, thespace between the outer perforated pipe/pipe system 6 and inner screen 7is filled with a matrix 8 having any wanted property. The matrix 8 mayfill the space alone or be a part of the combined liner and matrixelement system 4, e.g. as illustrated in FIG. 5 where a flexibleperforated material 9 between outer perforated tube/pipe system 6 andinner screen 7 forms a part of the combined liner/matrix element 4. Theflexible material 9 may be of any metal or polymer material. Material 9may be used in order to increase physical strength and stability ofmatrix element system 4. As material 9 is perforated it will not haveany significant influence on fluid flow through matrix 8 or throughholes or slices 10 through matrix 8.

[0038] In one embodiment holes or slices 10 through matrix 8 and innerscreen 7 gives free flow to any fluid 12 and/or fines 11 (e.g. sand)passing through outer tubular screen 6. This is shown in FIG. 6. A smallportion 14 of any fluid 12 is drained trough the porous matrix 8 by apressure gradient due to fluid streams 12 and 15 and different sizes orgeometric shapes of the holes or slices 10. The fluid flow 14 throughmatrix 8 enables any tracer incorporated into the matrix 8 to bereleased to the fluid stream 12 and thereafter to fluid stream 15 asdisclosed in Norwegian patent NO-C-309884, or to activate controlfunctions like swelling of matrix 8 when exposed to water for a giventime. The inner screen 7 protects the matrix 8 from erosion due to fluidflow 15 and it prevents the fluid flow 15 to wash out the tracer frommatrix 8 along its way out to the surface. This is an important issuesince the release of tracers from matrix 8 indicates the local fluidflow rate from each section as described in Norwegian patentNO-C-309884.

[0039]FIG. 7 shows another schematic cross wall drawing of a possibledesign for a combined liner and matrix element system 4, where holes orslices 10 through matrix 8 and inner screen 7 and a highly porousmaterial or screen 16 of any metal, polymer or composite materialbetween outer screen 6 and matrix 8, giving free flow to any fluidstream 12 and/or fines 11 (e.g. sand) passing through outer tubularscreen 6. A small portion 14 of any fluid stream 12 is drained throughthe porous matrix 8 by a pressure difference created by fluid streams 12and 15 and different sizes or geometric shapes of the holes or slices10, enabling any tracer to be released to fluid stream 12 according tothe mechanisms described in Norwegian patent NO-C-309884, or to activatecontrol functions like swelling of matrix 8 when exposed to water for agiven time. In this case also the inner screen 7 protects the matrix 8from erosion due to fluid flow 15 and it prevents the fluid flow 15 towash out the tracer from matrix 8 along its way out to the surface. Thisis an important issue since the release of tracers from matrix 8indicates the local fluid flow rate from each section as described inNorwegian patent NO-C-309884.

[0040] Perforated pipe/pipe system 6 may in principle be any combinationof perforated pipes, spacers and flexible material nets working as acombined liner and/or sand screener. FIG. 10 shows an embodiment wereperforated pipe system 6 is formed by an outer flexible material 19working as a sand screener, a perforated pipe 21 and a perforated pipe23. Between outer flexible material 19 and perforated pipe 21 andbetween perforated pipe 21 and perforated pipe 23 are spacers 20 and 22.Spacers 20 and 22 gives free flow of any fluid and/or fines comingthrough flexible material 19 alongside perforated pipes 21 and 23. Outerflexible material 19, spacer 20 and perforated pipe 21 may be formed byany commercial combined liner and sand screen system. Perforating holesthrough pipe 21 may be of any shape, number or sizes while perforatingholes through pipe 23 is coordinated with holes or slices through matrix8 and inner screen 7 as indicated for pipe/pipe system 6 in FIGS. 6 and7. Perforating holes in pipe 23 and holes or slices 10 through matrix 8and inner pipe 7 may be made in any way to prevent direct fluid flowthrough perforating holes in both pipes 21 and 23. Outer flexiblematerial 19, perforated pipes 21 and 23 and spacers 20 and 22 may be ofany material, polymer or composite material.

[0041] Matrix

[0042] An important concept in the present invention is accurate controlof the matrix porosity and the chemical composition. The matrix 8 ismade by filling the specific volume (bulk) with reagents that can reactto produce a porous polymer with the same shape as the free accessiblevolume. The porogen (often an inert solvent or polymers) is used tointroduce pores in the polymer matrix. The type and amount of porogenwill influence on the pore sizes and the degree of porosity. Evaporationor degradation of the porogen leads to permanent porous matrixes. Thematrix 8 may also consist of a bulk matrix as mentioned above combinedwith one or several types of prefabricated polymer particles. In thiscase the polymer particles are mixed with the monomer(s) or reagentsprior to the polymerization. During the polymerization process, theseparticles are evenly distributed throughout the whole volume of thematrix. The physical and chemical properties (e.g. porosity, pore size,degradability, swelling) are the same for a bulk matrix as for polymerto particles produced from the same amount and type of reagents.Different possibilities for manipulating the matrix are described belowfor polymer particles, but these also implies for a bulk polymer(matrix). Specially the pore sizes, the porosity and both the chemicaland physical properties may alter from the bulk matrix with respect tothe polymer particles when a combination of these types are used.Tailor-made matrixes (bulk and polymer particles) may be produced togive a controlled release of tracers and to control the permeabilitytowards different fluids.

[0043] The matrix may contain one or several type of porous or nonporouspolymer particles of given diameters from 0.2 μm to 5000 μm,preferentially 0.5 μm to 3000 μm and most preferentially 0.9 μm to 1000μm. Monodisperse or narrow sized particles may be produced by a two-stepswelling method (EP0003905) or in a step growth process (EP0594696B1).The two step swelling method is suitable for producing monodisperseparticles with sizes 1 μm to 1000 μm while the step growth process issuitable for producing particles with sizes 100 μm to 1000 μm. Porousparticles may be produced with a maximum pore volume of about 90percent, but higher pore volumes than 70% will give fragile particlesnot able to withstand large pressures at dry conditions. An optimum willbe particles with about 50 to 70 percent free pore volume. A high degreeof cross-linking in the particles will increase the amount of finepores, and depending on the type of porogen, pores with a radius ofabout 50 nm to 200 nm are easily made Larger pores are introduced by useof e.g. organic acids, alcohols, polymers or other degradableorganic/inorganic composites.

[0044] Polymer particles may be produced by other polymerizationtechniques like e.g. but not limited to dispersions, suspensions(oil/water), inverse suspensions, (water/oil), emulsions (mini- andmicro emulsions) or by condensation reactions. However, most of thesemethods will give a wider size distribution of the polymer particles inthe upper size range.

[0045] By mixing monodisperse or narrow sized particles of differentgiven sizes, special types of matrixes with desired porosity andpermeability can be made. Very accurate matrix packing structures may bemade using monodisperse particles. Predetermined changes to porosity andpermeability of the matrix due to given parameters like time,temperature, flow rate of oil, gas or water can be made

[0046] The pores in matrix 8 are filled with an inert medium orcompounds (porogen) after the polymerization process. Exposed to adesired medium (water or hydrocarbons), the porogen in the bulk matrixmay be replaced by the well fluid. Porogen or compounds inside porousparticles will dissolve at a slower rate giving a controlled change offree pore space and permeability of the matrix 8 in time

[0047] Degradable small compact/porous particles containing tracers mayalso be made and incorporated into the matrix By degradation (like asoap piece) these particles will not give ‘larger’ holes in the matrixincreasing porosity and permeability in time.

[0048] Degradable particles or gels present in the matrix may be made bysoluble polymers bound together with cross linking which may be brokenin time or exposed to e.g. water or oil When these bonds are broken, theparticles will be free to move with the fluid leaving open pores in thematrix.

[0049] Matrixes with different functional groups, like but not limitedto: —NH₂, —OH, —COOH, —CONH₂, —SH, —COOR (R is any group), may be madeby using monomers with specific chemical groups in addition to themonomers used for the polymerization reaction (described e.g. inEP0003905). By using given mixtures of different monomers, matrixes withdifferent properties may be made containing given amounts of functionalgroups.

[0050] Active substances like microorganisms or any tracer formonitoring hydrocarbon and water production from different productionzones/sections in a hydrocarbon reservoir and detection of differentphenomena such as e.g. local variations in pH, salinity, hydrocarboncomposition, temperature, pressure, microorganisms, and the differencebetween production of formation and/or injection water (described inNorwegian patent NO-C-309884) may be bound in the matrix 8 viadegradable bonds, like but not limited to: esters, anhydride, carbonateand schiff bases, acting on specific events.

[0051] Functional groups, like but not limited to —COOH, —OH, —CONH₂,—SO₃H, aromatic and aliphatic chains, may in addition be used in orderto give the matrix 8 wanted wetting properties (hydrophobic andhydrophilic).

[0052] Predetermined decrease of matrix porosity and permeability can bemade by use of swelling polymer particles or gels inside the matrix 8.The swelling properties may be obtained by using polymer/monomers whichcan e.g. hydrolyse in presence of water. In the hydrolysis or by otherchemical processes, hydrophilic groups (like but not limited to —COO⁻,—SO₃ ⁻ and —OH) are generated which gives increased solubility ofpolymer and swelling of particles/gels. If a cross-linked system isused, the degree of cross-linking will determine the degree of swellingof the matrix 8. A low degree of cross-linking will give a largeswelling. The principal for release of active substances or tracers isbased on fine and medium sized pores in the matrix 8, giving strengthand slow release of the active substance, as only a small part of thewell fluid will pass through the matrix 8 due to the pore size. Byintelligent incorporating tracers as part of the matrix 8 (described inNorwegian patent NO-C-309884) e.g. tracer as part of the monomer unit(s)a controlled release of tracers, without any decrease in matrixstability is ensured.

[0053] The matrix may comprise chemicals inhibiting or preventing anyunwanted phenomena as e.g. bacteria growth or scale formation in thematrix. A series of various chemicals can be immobilized in the matrix,which are controlled released or becoming active in response to givenunwanted phenomena in the matrix. The purpose of these chemicals is toavoid blockage of pores and growth on pore-walls in the matrix due tounwanted phenomena as e.g. growth of microorganisms or scale formation.The chemicals may be any suitable chemicals, preferentially working inlow concentrations.

[0054] The microorganisms primarily responsible for troubles inhydrocarbon reservoirs are the sulphate reducing bacteria (SRB). Theseorganisms are widely distributed and represent a specialised group ofmicroorganisms that are able to reduce sulphate (SO₄ ²⁻) to hydrogensulphide (H₂S). The conditions for growth and activity of SRB in anoffshore oil reservoir subjected to seawater flooding are good. Theenvironment is anaerobic, the seawater contains significant amounts ofsulphate and the formation of water and oil contains low molecular fattyacids as well as other nutrients. Thus, indigenous sulphate reducingbacteria (SRB) may colonise in the matrix and produce H₂S during growth.The H₂S may cause souring of the matrix and corrosion of the steelequipment, and the bacteria may produce biofilms (polysaccharides) thatresults in an unwanted plugging of pores in the matrix. Biocidetreatments are today used extensively to control bacterial activity andcorrosion in oil reservoirs and oil field systems. Toxic chemical usedis any convenient biocide (e.g. aldehydes, organic acids,isothiazolones, parabens, quatemary ammonium salts etc.).

[0055] Chemicals for biocide treatment immobilized in the matrix may bereleased or become active in response to certain triggers orSRB-metabolites. For example, the chemicals may be released or activatedin response to sulphide, which always is generated during growth ofmicroorganisms such as e.g. SRB, or in response to the lowering of pHthat results from sulphite production. In this situation, the chemicalswill be released only locally in regions with growth of SRB, while thechemicals in other regions remain latent and/or inactivated in thematrix. One possibility is to use magnetic iron (Fe) remanant particlesthat will coagulate and entrap or immobilize the chemical in its matrix.In response to sulphite (S²⁻) the iron will precipitate as FeS, thematrix will degrade and the biocide will be released. Polymers withcross-linkages based on cystamine may also be used. In the presence ofsulphite, the S—S-bond between two cystamine molecules will split andthe active agent will be released.

[0056] As with respect to release of active compounds in response tolowering of pH, various compounds or linkages that are labile at low pHcan be utilised. Biocidal aldehydes that are linked to a matrix as aShiff s base, will be released as a consequence of lowering of pH.Ester-linkages will also hydrolyse more effectively in acidicenvironments. Formation of biofilms, blocking pores in the matrix, maybe prevented by coating the pore walls with lectins or antibodiesagainst polysaccharides. Biofllm formed may be dissolved by e.g. use ofenzymes, preferentially from marine thermopile microorganisms, thatdegrades polysaccharides in the biofilm. Immobilized microorganisms inthe matrix with the ability to produce antimicrobial and/or growthrestraining compounds, e.g. antibiotics and bacteriocines, may also beused. In this respect genetic engineering may be used to designmicroorganisms with the ability to both grow and produce such compoundsunder reservoir conditions.

[0057] The matrix 8 may also be prefabricated onshore or offshore on anyplatform or ship by injecting a slurry containing given polymers and/orany polymer particles having desired properties, or containing anywanted chemicals or microorganism, initiators and an intern media (likebut not limited to: stabilized reservoir oil) between outer perforatedtubular pipe/pipe system 6 and inner screen 7. After polymerization thematrix will have a given porosity and permeability. In cases where inertmedia is used the pores in the matrix 8 made by the inert media willopen up in time as the inert media is washed out or released atreservoir conditions.

[0058] The temperature stability of the matrix 8 varies on the monomersused in the polymerization process and may vary from 50° C. to 300° C.

[0059] The physical strength of the bulk matrix or polymer particles (orcombinations thereof making up the matrix 8, may be influenced by thepore sizes. Compact particles have high physical strength while macroporous particles with a high pore volume are influenced by e.g. pressureand friction/shear forces.

[0060] When liner and matrix element system 4 is not to work for fluidcontrol of water or oil/gas, reservoir fluids and fines passing throughthe outer screen 6 will flow through matrix 8 and inner screens 7 (and16) without any significant pressure loss. Matrix 8 and inner screens 7and 16 are not to work as filters for fines like e.g. sand. This isaccomplished by larger openings in inner screen 7 and 16 than outerscreen 6 and or by either a high porosity of matrix 8, but morepreferably by holes or slices 10 through matrix 8 and inner screens 7and 16. The holes or slices 10 through matrix 8 and inner screens 7 and16 may be made by any suitable means and may be of any shape, size ornumbers but with larger open areas than holes or slices in screen 6.When matrix 8 swells by e.g. water, the open areas through holes orslices 10 through matrix 8 will decrease giving higher resistance tofluid flow through the liner and matrix element system 4. In some casesbefore installation in a reservoir free space formed by holes or slices10 may be filled with any desired inert medium or compound, making theliner and matrix element system 4 impermeable when introduced in a well.Exposed to reservoir conditions, a desired medium (water orhydrocarbons), or by any desired chemical trigger, or in time the inertmedium may dissolve at a given rate increasing fluid cross flow throughelement 4. In this way e.g. oil production rate can be delayed in timefor given parts/sections of the production zone in an oil well.

[0061] Considering the case when in e.g. a production zone in a well,the main content of fluids and all fines through outer screen 6 is toflow through element 4 nearly without any restrictions. For measuringand/or control functions a small portion of the fluids passing throughouter screen 6 is to pass through matrix 8. Inside matrix 8, tracers maydissolve into the fluid according to the applicant's patent NO-C-309884.The fluid flow inside matrix 8 may also initiate any wanted controlfunctions by matrix 8. The fluid flow 14 through matrix 8 is due topressure gradients caused by main fluid flow 13 through element 4, fluidflow 15 along element 4, shapes, sizes and numbers of holes or slices 10and inner screens 7 and 16 as illustrated in FIGS. 6 and 7. For enhancedfree flow of fluids 12 and any fines 11 through the element 4 and forprotection of matrix 8 from e.g. any well tools and erosion due to fluidflow 15 and for preventing the fluid flow 15 to wash out the tracersfrom matrix 8 along its way out to the surface, the holes or slices 10through matrix 8 may be coordinated by holes or slices in outer screen 6and inner screens 7 and 16 as illustrated in FIGS. 6 and 7.

[0062] Fluid control

[0063] A possible design for a water control function using a combinedliner and matrix element system 4 and swelling of matrix 8 is shown inFIG. 8. When matrix 8 is exposed to water fluid flow 12 for a giventime, or trigged by any desired chemical trigger 17 (from e.g. anyinjection well), the matrix 8 swells as illustrated in FIGS. 8A, B andC. When matrix 8 swells, pores in the matrix and holes or slices 10going through matrix 8 shrinks which results in decreases in free openareas in the matrix 8 increasing the flow resistance to the fluid flow12. The swelling of the matrix may be reversible according to thecontent of e.g. water or oil in the fluid flow 12 or may be permanent.

[0064] Another possible design for a fluid flow control function using acombined liner and matrix element system 4 is shown in FIG. 9. An inertmedium 18 is filled into pores in matrix 8 and holes or slices 10 goingthrough matrix 8 prior to installation of element 4 into a well 3.Exposed to reservoir conditions or trigged by any desired chemicaltrigger 17, the inert medium may be dissolved at a given rate opening uppores in matrix 8 and holes or slices 10 through matrix 8 as illustratedin FIGS. 9, A, B and C.

[0065] Elements of the combined liner and matrix element system 4 maypreferentially be prefabricated and tested onshore but may also beprefabricated and tested offshore on platforms or ships. It may be madein one or several lengths and or several outer and inner diameters.Mechanical strength, flexibility, physical and chemical properties ofinner screens 7 and 16 and outer screen 6 and matrix 8 may be variedaccording to requirements. Properties of the matrixes 8 may vary at anylength or circumference along the elements. The properties of thematrixes 8 may be predetermined from any reservoir data. In addition toa more or less permeable matrix 8 and holes or slices 10 through thematrix, the elements may contain parts of plain metal, polymer orcomposite material.

[0066] The elements 4 may be connected to each other, to otherconventional liner pipes or to any other kind of pipes (e.g. productiontubing) or equipment Together with any other pipeline segments orequipment the elements 4 may form a pipeline easily installed inhorizontal, vertical or helical production or injection wells. Thecombined liner and matrix element system may preferentially be installedfor once in a lifetime or made suitable for retrieval and reinstallationof new elements.

[0067] In addition to the use in any kind of well bore onshore and/oroffshore, similar combined perforated pipeline matrix system may be usedin any kind of process equipment (e.g. but not limited to: in reactors,separators, storage tanks, etc.).

[0068] Based on e.g. reservoir data a well bore may be divided intosections or zones that by optimum should be operating separately e.g. inorder to stop or restrict injection water to penetrate the hole wellbore. Sealing of the well bore in sections or zones may be done byinjection or squeezing of an impermeable matrix 5A in the free spacebetween a liner 5B and the well bore 3, This is shown in FIG. 4.Components for this matrix 5A may be encapsulated inside the combinedliner/matrix system elements 4 or squeezed throughout the screen 6 usingsuitable tools. Polymerization of the matrix 5A may be activated byremote control through any chemical, electrical, magnetic or mechanicalmeans. In order to prevent matrix 5A to form away from wanted placement,end sections may be temporary or permanent sealed off by any mechanicalor chemical means.

[0069] Having described preferred embodiments of the invention it willbe apparent to those skilled in the art that other embodimentsincorporating the concepts may be used. These and other examples of theinvention illustrated above are intended by way of example only and theactual scope of the invention is to be determined from the followingclaims.

1. Combined liner and matrix system (4) comprising an outer perforatedpipe/pipe system (6) having sufficient strength to work as a linerand/or a sand screener, an inner screen (7), and a matrix (8) arrangedbetween the outer pipe/pipe system (6) and inner screen (7), thecombined liner and matrix system constituting a prefabricated liner withpredefined properties for fast and simple well and/or reservoircompletion, monitoring and control.
 2. System according to claim 1,characterized in that the outer perforated pipe/pipe system (6) isformed as a flexible material net or as a single perforated pipe or asany combination thereof.
 3. System according to claim 1, characterizedin that the inner screen (7) is formed as a flexible material net or asa single perforated pipe.
 4. System according to claim 1, characterizedin that the outer perforated pipe/pipe system (6), the inner screen (7),and the matrix material (8) comprises a metal, inorganic or organicpolymer or composite material or any combinations thereof.
 5. Systemaccording to claim 1, characterized in a porous matrix (8), where theporosity, pore size and pore size distribution are controllable. 6.System according to claim 5, characterized in that the matrix (8)porosity/permeability is automatically affected by the environment, e.g.by temperature, water or oil flow, time or by manual trigging withspecific reagents.
 7. System according to claim 1, characterized in thatthe matrix (8) comprises at least one type of polymer or polymerparticles or a combination thereof.
 8. System according to claim 1,characterized in that the matrix (8) is either a bulk matrix having thesame shape as the geometrical volume of a polymer filling the matrix, apackage of at least one type of polymer particle or a combination ofpolymer particles in a bulk polymer.
 9. System according to claim 7 or8, characterized in that the polymer particles have a diameter from 0.2μm to 5000 μm.
 10. System according to claim 9, characterized in thatthe diameter preferably is from 0.5 μm to 3000 μm, and most preferablyfrom 0.9 μm to 1000 μm.
 11. System according to claim 1, characterizedin that the matrix (8) comprises a porogen medium or compound. 12.System according to claim 1, characterized in a porous matrix (8) or aninitially compact matrix (8), the compact matrix becoming porous andpermeable as a result of external influence, the matrix comprising apolymer or chemical compound reacting with the ambient conditions (e.g.temperature, pH, water or triggers) and thereby releasing substanceschemically bonded or bonded by adsorption to the matrix into the fluidflow.
 13. System according to claims 5 or 12, characterized in that thepore volume is from about 50 to 70% per free pore volume.
 14. Systemaccording to claim 1, characterized in that the matrix (8) comprisescomponents being detectable after release from the matrix.
 15. Systemaccording to claim 1, characterized in that the matrix (8) comprises achemically intelligent tracer(s) for monitoring specific events in thewell or reservoir.
 16. System according to claim 15, characterized inthat the tracers are adsorbed in or chemically bonded to the matrix (8).17. System according to claim 1, characterized in that the matrix (8)comprises chemicals inhibiting or preventing bacteria growth or scaleformation in the matrix (8).
 18. System according to claim 1,characterized in that the matrix/liner system (4) comprises a flexibleperforated material (9) of any metal or inorganic or organic polymer orany combinations thereof, between outer perforated pipe 6 and innerscreen 7, increasing physical strength and stability of the system. 19.System according to claim 1, characterized in that the inner screen (7)and matrix (8) comprises openings (10), said openings (10) having largeropen areas than in the outer perforated pipe/pipe system (6), givingfree flow of any fluid (12) and/or fines (11) passing through outerperforated pipe/pipe system (6).
 20. System according to claim 1,characterized in that the combined liner/matrix system (4) isprefabricated at any suitable length and connected to each other or toother pipeline elements forming a pipeline easily installable inhorizontal, vertical or helical wells.
 21. System according to claim 1,characterized in that the combined liner/matrix system (4) comprises asectional plugging system (5) for sealing off various sections of theliner/matrix system from each other.
 22. System according to claim 1,characterized in that the liner/matrix system (4) is divided in varioussections along the well, the matrix (8) having different properties inthe various sections.
 23. Method for control and monitoring of processesin a well or reservoir using the combined liner/matrix system accordingto claim 1, characterized in providing the matrix with certainproperties based on reservoir data prior to installation in thereservoir, installing the combined liner/matrix system in the reservoir,and controlling or monitoring the well by interaction with/by means ofthe matrix.
 24. Use of the combined liner/matrix system according to oneof claims 1-22 in any process equipment, like e.g. reactors, separatorsand storage tanks.
 25. Use of the liner/matrix system according to oneof claims 1-22 in a gas/oil/water producing or injection well for wellcompletion, control and monitoring.